This dialog allows the player to select the world for which they wish to battle. Four options are available:
Generate Random World - This option will allow the player to select the size of world desired, and then have the game create a random world based on the size.
Generate Named World - This option allows the player to select from millions of worlds. You'll be asked for the (fictional) name of the world, and it will be generated for you.
Load World Map - This option allows the player to select a previously-built world created with the map editor or saved from within a game in progress as a "map".
Load Game Scenario - This option allows the player to select a scenario previously created with the map editor or saved from within a game in progress as a "scenario".